The practice of making bacterial cultures to determine the number of type of bacteria present in food, pharmaceutical products, etc. is conventionally known.
Now then, the bacterial culture medium is made in some dishes that are known as Petri dishes in which a base product that consists of a gelled agar-agar solution that constitutes food for the bacteria is placed, upon which an extract of the product to be analyzed is placed.
Subsequently the dish is placed in an oven to favor the reproduction of the bacteria, creating different colonies from each microorganism present in the extract of the product to be analyzed.
The problem that arises afterwards consists of making the count of colonies created, in order to establish the amount of bacteria that was contained in the analyzed product.
Conventionally the count is made visually directly or by means of a magnifying glass, which makes it a task that requires a great visual effort and a great deal of concentration, thus, the probability that errors are made in the counts made is considerable, a probability that increases when the operator has to make the count of countless bacterial cultures, since this operation really tires out the person who has to carry it out.
Besides, automatic counting apparatus of bacterial colonies that are based on illuminating the dish and on detecting the image of the same, by means of a video camera, exist. These devices have the problem that multiple reflections are created since the base product coagulates, on occasions, very rapidly and the surface thereof has waves, aside from the bubbles that may appear in the base product, as well as the reflections that the walls themselves of the dish, base and cover thereof create; therefore, it is necessary to remove the cover from the dish to make the count of the bacterial colonies, with the subsequent risk of contamination, that this operation involves, for the user as well as for the culture, aside from the bad smells that are given off upon opening the dish.
Another problem that these devices have consists of the fact that the handling of the dishes is totally manual which makes the process more expensive and hampers the carrying out of the same.
Besides, the dishes are arranged inside the oven, in stacks, the bases contacting with each other, therefore the thermal balance is not attained at the most suitable speed to achieve homogeneous reproduction of colonies in all of the dishes.